[jsdl-wg] SPMD woes...

[Andre Merzky]

Hi Andreas, 

Quoting [Andreas Savva] (Mar 08 2010):
> 
>> So, here is the biggie: Is JSDL at some point considering to revise
>> the SPMD spec?
> 
> Yes, it's definitely possible given new use cases and sufficient
> enthusiasm.

Use cases we can provide, enthusiasm too, but actual time ... - lets
see ;-)

FWIW, we have been  discussing the mentioned issues with the DRMAA
group, too - those guys come to similar conclusions, and may also be
interested to drive this forward.


>> If so, can we expect something along the lines
>> above, or is that, aehem, 'out of scope'?  If not, how would you
>> propose to align the SAGA use cases with JSDL/Glue/..., so that we
>> still end up with an implementable standards stack?
> 
> We don't have an automatic 'out of scope' filter, contrary to popular
> belief. :-) 

Hehe - well, your t-shirts fostered that believe I think ;-)


> But for obvious reasons I cannot guarantee you a specific
> outcome ahead of time. 

Oops, I guess I should have  formulated that more carefully...  Of
course you can't guarantee anything.  Question should have been:
does that sound like a sensible road to pursue to you?


> The end result depends on what use cases people think important.
> From what I heard in the past a number of people seem interested
> in adding 'core' support to spmd. If cores are adequately
> represented in the Glue schema, which we said we are going to use
> for future jsdl resource requirements, I would imagine it would
> not be a big deal; once other pieces are in place.

Yes - given your corrections about the JSDL semantics you provided,
it seems indeed that the missing support for cores and hardware
threads are the central point.


> The spec (p4 & p8) is clear that spmd elements are intended to
> describe the application not its resources.

Right, makes sense.  The problem IMHO is that the application layout
depends on the specific resource it is being maped to, and that
dependency is hard to express.


> Let's talk about your use cases at OGF. I can try to arrange some
> time for this topic in the jsdl general session if you like.

We would also be happy to host that in one of the SAGA sessions, if
you find it difficult to accomodate that topic in the agenda.  But
yes, discussing at OGF seems sensible.

See you next week then! :-)

Cheers, Andre.



-- Nothing is ever easy.